Grok 4 Fast Non-Reasoning is the speed-optimized, non-reasoning variant of xAI's Grok 4 Fast. It delivers fast inference without chain-of-thought overhead, tailored for high-throughput applications within a context window of 2M tokens.
import { streamText } from 'ai'
const result = streamText({ model: 'xai/grok-4-fast-non-reasoning', prompt: 'Why is the sky blue?'})Grok 4 Fast Non-Reasoning is the non-reasoning configuration of xAI's Grok 4 Fast model, released September 19, 2025. It disables the extended chain-of-thought reasoning process, producing direct answers without intermediate reasoning traces. This eliminates reasoning token overhead and reduces both latency and output cost per request.
The model builds on the Grok 4 training foundation, carrying forward its language understanding and instruction following capabilities, but operates in a direct-response mode optimized for speed. With a context window of 2M tokens, it handles general-purpose tasks including text generation, summarization, classification, and tool calling.
Grok 4 Fast Non-Reasoning is available at $0.2 per million input tokens and $0.5 per million output tokens through Vercel AI Gateway. It pairs naturally with its reasoning counterpart: use the non-reasoning variant for straightforward tasks and the reasoning variant when analytical depth is needed.